Fascinating thread....it some respects the general thread doesn't match the usual "tone" of TE. I would have thought there would be more answers along the lines lph and Lisa and less that lean towards getting rid of the friend. Hmmm.....

Personally, I'm a geek. Always have been. Always will be (I suspect). Since I was a kid, I've had friends who were male. DH has friends who are female. Neither of us has problems with this. My life would not be as rich if I thought I couldn't have friends of the opposite gender. I wouldn't try to control DH's life by dictating friends and I wouldn't want DH to dictate mine. It comes down to trust.

Like jobob, I wonder if the problem really isn't that the riding buddy is male so much as it is that you're spending a lot of "fun time" without him. If the latter is the case, then as his fitness improves, perhaps the problem will lessen? One would hope this is the case--jealousy is not healthy in a relationship. Better to find out the underlying cause than just treating the symptom.